{Reference Type}: Journal Article {Title}: Preclinical Evaluation of TB/FLU-04L-An Intranasal Influenza Vector-Based Boost Vaccine against Tuberculosis. {Author}: Shurygina AP;Zabolotnykh N;Vinogradova T;Khairullin B;Kassenov M;Nurpeisova A;Sarsenbayeva G;Sansyzbay A;Vasilyev K;Buzitskaya J;Egorov A;Stukova M; {Journal}: Int J Mol Sci {Volume}: 24 {Issue}: 8 {Year}: 2023 Apr 18 {Factor}: 6.208 {DOI}: 10.3390/ijms24087439 {Abstract}: Tuberculosis is a major global threat to human health. Since the widely used BCG vaccine is poorly effective in adults, there is a demand for the development of a new type of boost tuberculosis vaccine. We designed a novel intranasal tuberculosis vaccine candidate, TB/FLU-04L, which is based on an attenuated influenza A virus vector encoding two mycobacterium antigens, Ag85A and ESAT-6. As tuberculosis is an airborne disease, the ability to induce mucosal immunity is one of the potential advantages of influenza vectors. Sequences of ESAT-6 and Ag85A antigens were inserted into the NS1 open reading frame of the influenza A virus to replace the deleted carboxyl part of the NS1 protein. The vector expressing chimeric NS1 protein appeared to be genetically stable and replication-deficient in mice and non-human primates. Intranasal immunization of C57BL/6 mice or cynomolgus macaques with the TB/FLU-04L vaccine candidate induced Mtb-specific Th1 immune response. Single TB/FLU-04L immunization in mice showed commensurate levels of protection in comparison to BCG and significantly increased the protective effect of BCG when applied in a "prime-boost" scheme. Our findings show that intranasal immunization with the TB/FLU-04L vaccine, which carries two mycobacterium antigens, is safe, and induces a protective immune response against virulent M. tuberculosis.